MSC-derived exosomes protect auditory hair cells from neomycin-induced damage via autophagy regulation

Background Sensorineural hearing loss (SNHL) poses a major threat to both physical and mental health; however, there is still a lack of effective drugs to treat the disease. Recently, novel biological therapies, such as mesenchymal stem cells (MSCs) and their products, namely, exosomes, are showing promising therapeutic potential due to their low immunogenicity, few ethical concerns, and easy accessibility. Nevertheless, the precise mechanisms underlying the therapeutic effects of MSC-derived exosomes remain unclear. Results Exosomes derived from MSCs reduced hearing and hair cell loss caused by neomycin-induced damage in models in vivo and in vitro. In addition, MSC-derived exosomes modulated autophagy in hair cells to exert a protective effect. Mechanistically, exogenously administered exosomes were internalized by hair cells and subsequently upregulated endocytic gene expression and endosome formation, ultimately leading to autophagy activation. This increased autophagic activity promoted cell survival, decreased the mitochondrial oxidative stress level and the apoptosis rate in hair cells, and ameliorated neomycin-induced ototoxicity. Conclusions In summary, our findings reveal the otoprotective capacity of exogenous exosome-mediated autophagy activation in hair cells in an endocytosis-dependent manner, suggesting possibilities for deafness treatment.

Inhibition of histone methyltransferase PRMT5 attenuates cisplatin-induced hearing loss through the PI3K/Akt-mediated mitochondrial apoptotic pathway / 药物分析学报

This study aimed to evaluate the therapeutic potential of inhibiting protein arginine methyltransferase 5(PRMT5)in cisplatin-induced hearing loss.The effects of PRMT5 inhibition on cisplatin-induced auditory injury were determined using immunohistochemistry,apoptosis assays,and auditory brainstem response.The mechanism of PRMT5 inhibition on hair cell survival was assessed using RNA-seq and Cleavage Under Targets and Tagment-quantitative polymerase chain reaction(CUT&Tag-qPCR)analyses in the HEI-OC1 cell line.Pharmacological inhibition of PRMT5 significantly alleviated cisplatin-induced damage to hair cells and spiral ganglion neurons in the cochlea and decreased apoptosis by protecting mitochondrial function and preventing the accumulation of reactive oxygen species.CUT&Tag-qPCR analysis demonstrated that inhibition of PRMT5 in HEI-OC1 cells reduced the accumulation of H4R3me2s/H3R8me2s marks at the promoter region of the Pik3ca gene,thus activating the expression of Pik3ca.These findings suggest that PRMT5 inhibitors have strong potential as agents against cisplatin-induced ototoxicity and can lay the foundation for further research on treatment strategies of hearing loss.

Aligned Organization of Synapses and Mitochondria in Auditory Hair Cells / 神经科学通报·英文版

Recent studies have revealed great functional and structural heterogeneity in the ribbon-type synapses at the basolateral pole of the isopotential inner hair cell (IHC). This feature is believed to be critical for audition over a wide dynamic range, but whether the spatial gradient of ribbon morphology is fine-tuned in each IHC and how the mitochondrial network is organized to meet local energy demands of synaptic transmission remain unclear. By means of three-dimensional electron microscopy and artificial intelligence-based algorithms, we demonstrated the cell-wide structural quantification of ribbons and mitochondria in mature mid-cochlear IHCs of mice. We found that adjacent IHCs in staggered pairs differ substantially in cell body shape and ribbon morphology gradient as well as mitochondrial organization. Moreover, our analysis argues for a location-specific arrangement of correlated ribbon and mitochondrial function at the basolateral IHC pole.

Effect of Sodium Salicylate on Calcium Currents and Exocytosis in Cochlear Inner Hair Cells: Implications for Tinnitus Generation / 神经科学通报·英文版

Sodium salicylate is an anti-inflammatory medication with a side-effect of tinnitus. Here, we used mouse cochlear cultures to explore the effects of salicylate treatment on cochlear inner hair cells (IHCs). We found that IHCs showed significant damage after exposure to a high concentration of salicylate. Whole-cell patch clamp recordings showed that 1-5 mmol/L salicylate did not affect the exocytosis of IHCs, indicating that IHCs are not involved in tinnitus generation by enhancing their neuronal input. Instead, salicylate induced a larger peak amplitude, a more negative half-activation voltage, and a steeper slope factor of Ca2+ current. Using noise analysis of Ca2+ tail currents and qRT-PCR, we further found that salicylate increased the number of Ca2+ channels along with CaV1.3 expression. All these changes could act synergistically to enhance the Ca2+ influx into IHCs. Inhibition of intracellular Ca2+ overload significantly attenuated IHC death after 10 mmol/L salicylate treatment. These results implicate a cellular mechanism for tinnitus generation in the peripheral auditory system.

Glucose Protects Cochlear Hair Cells Against Oxidative Stress and Attenuates Noise-Induced Hearing Loss in Mice / 神经科学通报·英文版

Oxidative stress is the key determinant in the pathogenesis of noise-induced hearing loss (NIHL). Given that cellular defense against oxidative stress is an energy-consuming process, the aim of the present study was to investigate whether increasing energy availability by glucose supplementation protects cochlear hair cells against oxidative stress and attenuates NIHL. Our results revealed that glucose supplementation reduced the noise-induced formation of reactive oxygen species (ROS) and consequently attenuated noise-induced loss of outer hair cells, inner hair cell synaptic ribbons, and NIHL in CBA/J mice. In cochlear explants, glucose supplementation increased the levels of ATP and NADPH, as well as attenuating H

ROS Scavenger, Ebselen, Has No Preventive Effect in New Hearing Loss Model Using a Cholesterol-Chelating Agent

BACKGROUND AND OBJECTIVES: The antioxidant ebselen will be able to limit or prevent the ototoxicity arising from 2-hydroxypropyl-β-cyclodextrin (HPβCD). Niemann-Pick Type C (NPC) disease is a disorder of lysosomal storage manifested in sphingolipidosis. Recently, it was noted that experimental use of HPβCD could partially resolve the symptoms in both animals and human patients. Despite its desirable effect, HPβCD can induce hearing loss, which is the only major side effect noted to date. Understanding of the pathophysiology of hearing impairment after administration of HPβCD and further development of preventive methods are essential to reduce the ototoxic side effect. The mechanisms of HPβCD-induced ototoxicity remain unknown, but the resulting pathology bears some resemblance to other ototoxic agents, which involves oxidative stress pathways. To indirectly determine the involvement of oxidative stress in HPβCD-induced ototoxicity, we tested the efficacy of an antioxidant reagent, ebselen, on the extent of inner ear side effects caused by HPβCD. MATERIALS AND METHODS: Ebselen was applied prior to administration of HPβCD in mice. Auditory brainstem response thresholds and otopathology were assessed one week later. Bilateral effects of the drug treatments also were examined. RESULTS: HPβCD-alone resulted in bilateral, severe, and selective loss of outer hair cells from base to apex with an abrupt transition between lesions and intact areas. Ebselen co-treatment did not ameliorate HPβCD-induced hearing loss or alter the resulting histopathology. CONCLUSIONS: The results indirectly suggest that cochlear damage by HPβCD is unrelated to reactive oxygen species formation. However, further research into the mechanism(s) of HPβCD otopathology is necessary.

In vitro culture of mammalian inner ear hair cells / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Auditory function in vertebrates depends on the transduction of sound vibrations into electrical signals by inner ear hair cells. In general, hearing loss resulting from hair cell damage is irreversible because the human ear has been considered to be incapable of regenerating or repairing these sensory elements following severe injury. Therefore, regeneration and protection of inner ear hair cells have become an exciting, rapidly evolving field of research during the last decade. However, mammalian auditory hair cells are few in number, experimentally inaccessible, and barely proliferate postnatally in vitro. Various in vitro primary culture systems of inner ear hair cells have been established by different groups, although many challenges remain unresolved. Here, we briefly explain the structure of the inner ear, summarize the published methods of in vitro hair cell cultures, and propose a feasible protocol for culturing these cells, which gave satisfactory results in our study. A better understanding of in vitro hair cell cultures will substantially facilitate research involving auditory functions, drug development, and the isolation of critical molecules involved in hair cell biology.

Differential Expression of Ca²⁺-buffering Protein Calretinin in Cochlear Afferent Fibers: A Possible Link to Vulnerability to Traumatic Noise

The synaptic contacts of cochlear afferent fibers (CAFs) with inner hair cells (IHCs) are spatially segregated according to their firing properties. CAFs also exhibit spatially segregated vulnerabilities to noise. The CAF fibers contacting the modiolar side of IHCs tend to be more vulnerable. Noise vulnerability is thought to be due to the absence of neuroprotective mechanisms in the modiolar side contacting CAFs. In this study, we investigated whether the expression of neuroprotective Ca²⁺-buffering proteins is spatially segregated in CAFs. The expression patterns of calretinin, parvalbumin, and calbindin were examined in rat CAFs using immunolabeling. Calretinin-rich fibers, which made up ~50% of the neurofilament (NF)-positive fibers, took the pillar side course and contacted all IHC sides. NF-positive and calretinin-poor fibers took the modiolar side pathway and contacted the modiolar side of IHCs. Both fiber categories juxtaposed the C-terminal binding protein 2 (CtBP2) puncta and were contacted by synaptophysin puncta. These results indicated that the calretinin-poor fibers, like the calretinin-rich ones, were afferent fibers and probably formed functional efferent synapses. However, the other Ca²⁺-buffering proteins did not exhibit CAF subgroup specificity. Most CAFs near IHCs were parvalbumin-positive. Only the pillar-side half of parvalbumin-positive fibers coexpressed calretinin. Calbindin was not detected in any nerve fibers near IHCs. Taken together, of the Ca²⁺-buffering proteins examined, only calretinin exhibited spatial segregation at IHC-CAF synapses. The absence of calretinin in modiolar-side CAFs might be related to the noise vulnerability of the fibers.

Low Frequency Noise of Acute Exposure to Bama Fragrant Pig Hair Cell Damage / 听力学及言语疾病杂志

Objective To investigate the effect of intense low frequency noise on the different hearing functions and hair cell damage in bama pigs.Methods Thirteen bama pigs were randomly divided into a normal control group (3 pigs) and an experimental group (10 pigs).The pigs in experimental group were randomly divided into 50 Hz subgroup (5 pigs) and 70 Hz subgroup (5 pigs).The 50 Hz subgroup was exposed to intense low frequency noise at 167～170 dB SPL,50 Hz for 30 min,and the 70 Hz subgroup was exposed to intense low frequency noise at 164 dB SPL,70 Hz for 30 min.Auditory brainstem response(ABR) and distortion product otoacoustic emission (DPOAE) were performed before and after noise exposure.The cochlear were collected and the inner ear morphology changes were studied.Results Before the experiment,the ABR threshold of the pig was 20～50 dB SPL,and the average of 50 Hz group was 33.5±9.4 dB SPL,the average of the 70 Hz group was 34.0±4.6 dB SPL.The level of the above 3 000 Hz DPOAE could be elicited.But they were not elicited after the exposure to the noise.The inner ear structures were damaged.The DAPI showed hair cell missing.Conclusion ABR and DPOAE were elevated after noise exposure.The auditory system of bama pigs had irreversible damages.Hair cells damaged were given priority to with necrosis,and the higher the level of intense low frequency noise,the more serious the damage to the hair cell.

The role of β-catenin deletion in Sox2-positive cells in inner-ear development and polarity regulation in mice / 复旦学报（医学版）

Objective To investigate the role of β-catenin,the core protein of canonical Wnt/β-catenin signaling,in the inner-ear development and polarity regulation.Methods β-catenin was conditionally deleted from precursor cells of inner-ear sensory epithelium (Sox2-positive cells) in embryonic mice.Morphological changes of the inner ear were observed.Immunofluorescence staining was performed to basilar membranes,utricles and saccules to observe the hair-cell changes in arrangement and polarity.Results Compared with the control group,knock-out of β-catenin in Sox2-positive cells resulted in smaller otic vesicles,cochleas and vestibules,and fewer hair cells (HCs) in vestibular sensory epithelium (P＜0.01).Stereocilium showed misorientation and kinocillia had a change in location and quantity in the cochlea.Scattered misorented HCs were also observed in the vestibule.Conclusions β-catenin is crucial for the development of inner ear and polarity manipulation of HCs in mice.The canonical Wnt/β-catenin signaling may be involved in the regulation of cochlea extension and planar cell polarity (PCP) of inner ear,which is known to be controlled by non-canonical Wnt/PCP signaling.

Role of Wnt/β-catenin signaling in zebrafish lateral line hair cell regeneration / 中国耳鼻咽喉头颈外科

OBJECTIVE To explore the role of Wnt/β-catenin signaling in hair cell regeneration using zebrafish lateral line system. METHODS Zebrafish larval were incubated in cisplatin solution to induce lateral line hair cells loss and then regenerated for 48 hrs. Supporting cells were sorted, and QPCR was taken to detect the expression change of Wnt/β-catenin signaling factors. Whole mount in situ hybridization was used to show the expression pattern of dkks. Wnt/β-catenin signalinginhibitors(FH535 and XAV939) and enhancer(BIO) was added to the medium to observe the influences on hair cell regeneration. RESULTS RT-PCR and Q-PCR showed that the expressions of wnt2, wnt3a and ctnnb1 in sorting supporting cells were elevated(P＜0.05). Whole mount in situ hybridization showed that the expression of dkk1a and dkk2 in lateral lines sub-supporting cellsreduced. The addition of Wnt/β-catenin signaling inhibitors reduced the regenerated hair cells to 40％ of normal, and even to 10％ when the concentration of inhibitor was elevated.And the first 12 hrs Wnt/β-catenin signaling inhibition also led to the reduced regenerated hair cells(P＜0.001). However, regeneratedhair cells have no significant change compared between BIO-treated and nontreated group(P＞0.05). CONCLUSION Wnt/β-catenin signaling is necessary whilenot sufficient for zebrafish lateral line hair cell regeneration.

Locacorten Vioform Ototoxicity Upon Guinea Pig Middle Ear Application

BACKGROUND AND OBJECTIVES: Locacorten Vioform (Novartis UK) is frequently prescribed for otomycosis. Its component, Clioquinol, also has anti-bacterial properties. Up to this point, its ototoxic potential has not been evaluated. Our objective aims to evaluate Locacorten Vioform’s potential ototoxicity when applied directly to the middle ear cavity. MATERIALS AND METHODS: We performed an experimental prospective animal study in our animal research center with 20 Hartley guinea pigs divided into 2 groups. The first group (experimental) was treated with Locacorten Vioform in one ear and with a physiologic saline solution in the other. The second group (positive control) was treated with concentrated gentamycin in one ear and physiologic saline in the other. Auditory brainstem response measurements were obtained before and after three sets of injections. Statistics were analyzed using a variance analysis with repeated measures. The histological state of cochlear outer hair cells was compared between the two groups using scanning electron microscopy. RESULTS: Average hearing loss in ears treated with Locacorten Vioform was 32.1 dB, compared with a 2.5 dB average loss in the saline-treated ears. Ears treated with gentamycin lost an average of 33.0 dB. There were clinically and statistically significant differences between the two ears of the guinea pigs in both groups (p < 0.001). Scanning electron microscopy revealed severe pericochlear and cochlear inflammation and ossification in the Locacorten Vioform-treated ears. Gentamycin caused significant destruction of outer hair cell architecture. CONCLUSIONS: Locacorten Vioform induces a hearing loss similar to that caused by gentamycin when applied directly to the middle ear of a guinea pig model. Electron microscopy indicates a pericochlear and cochlear inflammatory reaction with ossification.

Advances in the biological restoration of the hearing / 复旦学报（医学版）

Sensorineural deafness is the most common disorders of senses,which severely impact the life quality and bring heavy burden to the family as well as the society.Current state-of-art treatments focus on sound amplification and implanted electrodes that stimulate the auditory nerve.These strategies offer partial recovery of function for a limited patient population but do not come close to restoring natural hearing.Clearly,there is strong need for development of biological treatments for the hearing restoration through correcting the genetic defects or regenerating the new hair cells on the damaged cochlear sensory epithelium.We reviewed the advances in the biological restoration of the hearing,including the gene therapy and the hair cell regeneration aspects.

Noise-Induced Acetyl-histone H2B Expression Alteration in Cochlear Basilar Membrane of Guinea Pigs / 听力学及言语疾病杂志

Objective To study the changes of acetyl-histone H2B in the cochlear hair cells of the guinea pig model of noise-induced hearing loss (NIHL).Methods Sixty guinea pigs were randomly divided into control and noise-exposure group.Thirty guinea pigs in the noise-exposure group were exposed to narrowband noise at 122 dB SPL for 3 hours , while thirty guinea pigs in the control group were not exposed to noise.Auditory thresholds were assessed by auditory brainstem response (ABR), prior to noise in two groups and 3, 7,14 and 21 days after noise exposure in the noise group.Then we investigated the expression of acetyl-histone H2B levels in the sensory cells of basilar membrane after noise expose by immunofluorescence staining and western blot.Results Compared with pre-exposure hearing, ABR thresholds were increased at 1h, 3, 7, 14 and 21 days after noise exposure, and recovered gradually with time and reached a permanent threshold shift at 14 days.The expression of acetyl-histone H2B was down-regulated in the hair cells and Hensen''s cells of the guinea pig cochlea after the noise expose , The ratio of H2B-AcK5 / β-actin was 0.6179±0.1260 in the control group and 0.3102±0.0839 in the noise group, and the difference was statistically significant (P<0.01).Conclusion Noise decreased the inner ear sensory cells histone acetylation level and histone acetylation imbalance may be involved in the occurrence of NIHL.

Differentiation of Human Umbilical Cord Mesenchymal Stem Cells into Hair-cell Like Cells in Vitro / 听力学及言语疾病杂志

Objective To induce human umbilical cord mesenchymal stem cells (hUC-MSCs) to hair-cell like cells in the inner ear, using a two-step neural differentiation method.Methods The hUC-MSCs were obtained from human umbilical cords by tissue adherence culture,whose surface antigen CD29, CD34, CD44, CD45, CD90, HLA-ABC, and HLA-DR could be identified by flow cytometry.In the neural stem cells induced phase, the NSE positive cells were analyzed by microscope and immunohistochemistry.In the second stage, the expression of hair-cell like cells markers (Math1, MyosinⅦa, Brn3c) were tested by qRT-PCR and immunofluorescence method.Results The control group and the protocol group had little NSE after differentiation while the protocol B group presented a neurobiological structure and demonstrated a higher NSE positive ratio after 5 days' neural stem cells induction (P<0.05).Compared to the control group, the mRNA and protein level of Math1, MyosinⅦa, and Brn3c exhibited a significant increase in the differential group,which induced for 4 weeks in the hair-cell like cells in the inner ear's induced phase(P<0.05).Conclusion The two-stage induction (hUC-MSCs-neural stem cells-hair-cell like cells) could produce more MyosinⅦa,Brn3c and Math1,which may provide an appropriate way to treat sensorineural deafness.

Inhibition of K⁺ outward currents by linopirdine in the cochlear outer hair cells of circling mice within the first postnatal week

Inhibition of K⁺ outward currents by linopirdine in the outer hair cells (OHCs) of circling mice (homozygous (cir/cir) mice), an animal model for human deafness (DFNB6 type), was investigated using a whole cell patch clamp technique. Littermate heterozygous (+/cir) and ICR mice of the same age (postnatal day (P) 0 –P6) were used as controls. Voltage steps from –100 mV to 40 mV elicited small inward currents (–100 mV~–70 mV) and slow rising K⁺ outward currents (–60 mV ~40 mV) which activated near –50 mV in all OHCs tested. Linopirdine, a known blocker of K⁺ currents activated at negative potentials (I(K,n)), did cause inhibition at varying degree (severe, moderate, mild) in K⁺ outward currents of heterozygous (+/cir) or homozygous (cir/cir) mice OHCs in the concentration range between 1 and 100 µM, while it was apparent only in one ICR mice OHC out of nine OHCs at 100 µM. Although the half inhibition concentrations in heterozygous (+/cir) or homozygous (cir/cir) mice OHCs were close to those reported in I(K,n), biophysical and pharmacological properties of K⁺ outward currents, such as the activation close to –50 mV, small inward currents evoked by hyperpolarizing steps and TEA sensitivity, were not in line with I(K,n) reported in other tissues. Our results show that the delayed rectifier type K⁺ outward currents, which are not similar to I(K,n) with respect to biophysical and pharmacological properties, are inhibited by linopirdine in the developing (P0~P6) homozygous (cir/cir) or heterozygous (+/cir) mice OHCs.

The Effects of Cisplatin on the Expression of Calpain in Mouse Cochlear Hair Cell in Vitro / 听力学及言语疾病杂志

Objective To investigate the effects of cisplatin on the expression of calpain in mouse cochlear hair cells in vitro ,and to explore the mechanism of cisplatin-induced apoptosis in mouse cochlear hair cells .Meth‐ods A total of 600 cochlear basilar membranes isolated from Kunming mice at postnatal day 3 were cultured for 24 hours ,then randomly divided into control group and 3 cisplatin groups (4 μg/ml ,8 μg/ml and 16 μg/ml) .Each group contained 150 basilar membranes .Four groups were continually cultured for another 24 hours .Hoechst 33258 staining was used to detect the apoptosis of cochlear hair cell .Immunofluorescent staining and Western blot were carried out for detecting the expressions of calpain 1 (μ-calpain) and calpain 2 (m-calpain) in mouse cochlear hair cells .Results The percent of apoptotic hair cells in the three cisplatin groups (15 .63% ± 0 .20% ,38 .40% ± 2 .64% and 64 .24% ± 0 .05% ,respectively) was greater than that of in the control group (5 .55% ± 0 .12% ) , showing a clear dose-response relationship (P<0 .01) .Furthermore ,the expressions of μ -calpain and m -cal‐pain in different cisplatin groups were increased ,and m -calpain expression was great remarkably with increased concentration of cisplatin (P<0 .01) .Conclusion Our results suggest that cisplatin can induce the apoptosis in mouse cochlear hair cells by regulating calpain pathway .This may play a role in the cisplatin-induced ototoxicity .

The Observation of Cochlea Hair Cell Death and Expression of Caspase-3 after Intense Low Frequency Noise Exposure in Bama Pig / 听力学及言语疾病杂志

Objective To investigate the effects of intense low frequency noise on expression of caspase -3 in bama pigs ,and observe the death of cochlea hair cell .Methods 8 bama pigs were randomly divided into a normal control group(2 pigs) and experimental groups(6 pigs) .Auditory brainstem responses(ABR) were tested before the experiment .The control group was the same as the experimental groups except noise exposure .The experimental group was randomly divided into immediate group ,36 h group ,and 84 h group(2 pigs per group) .They were ex-posed to intense low frequency noise at 142 dB of 50 Hz for 5 min according to the three time points .ABR were test-ed again before the cochlea were collected at different time points .The expression of caspase -3 was studied through immunohistochemistry and immunofluorescence ,hair cell loss rate by counting to determine cell death .Results The average ABR threshold of 8 bama pigs(16 ears) before the exposure was 61 .25 ± 10 .72 dB nHL .ABR thresh-olds were not elicited after exposure to the noise .Different parts of bama pigs showed positive expression of caspase -3 in two ways .As time prolonged after exposure ,the positive expression of caspase -3 gradually weakened .The im-mediate group and 36 h group ,compared with the control group ,showed the apparent misplace of three out hair cells in the arrangement and levels .The 84 h group through immunofluorescence lost out hair cells ,and only inner hair cells were visible .Conclusion ABR thresholds were elevated after noise exposure .The procedure of hair cell nucleus damage and caspase-3 expression is different ,and the noise can induce opening apoptotic program of spiral ganglion .

Valuation of Transient Evoked Otoacoustic Emissions and Distortion Product Otoacoustic Emissions in Tinnitus Patients with Normal Hearing / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: This study aims to verify that one of the causes of tinnitus is the malfunction of outer hair cells and, on the basis of this, to investigate the usefulness of otoacoustic emissions by performing transient evoked otoacoustic emissions (TEOAE) and distor-tion product otoacoustic emissions (DPOAE). SUBJECTS AND METHOD: Included in the study were forty-one patients who had normal hearing in the range from 0.5 to 8 kHz, and complained of unilateral tinnitus. In these patients, hearing in bilateral ears, TEOAE, DPOAE, as well as the frequency & amplitude of their tinnitus were measured. RESULTS: No statistically significant difference was found in bilateral hearing in patients who complained of unilateral tinnitus. However, TEOAE and DPOAE showed a statistically significant difference with their p-values at 0.04 and 0.004, respectively. CONCLUSION: The results of this study suggested that TEOAE testing and DPOAE testing provide an important clue for verifying that the loss of outer hair cells contributed to the development of symptoms suffered by tinnitus patients with normal hearing.

Cell death type of zebrafish lateral line hair cellsinduced by cisplatin / 中国耳鼻咽喉头颈外科

OBJECTIVE To explore cell death type of lateral line hair cellsinduced by cisplatin in zebrafish. METHODS Zebrafish larva were incubated in 1mM cisplatin solution for 6 hrs to induce about 90%lateral line hair cells loss. Time lapse imaging was used to detect the morphology of cisplatin-incubated hair cells in wildtypezebrafish pre-labelled by live dyes Bodipy TR C5-ceramide and Sytogreen 24. TUNEL assay and In situ anti-active Caspase-3 antibody staining were performed to detect nuclei fragmentation and Caspase-3 activity respectively. RESULTS Compared to control group, hair cells condensationand nuclei fragmentation (P<0.05) were detected in cisplatin-incubated group, and active Caspase-3 activity was also observed after cisplatin addition. CONCLUSION Cisplatinmay induced zebrafish lateral line hair cells loss by Caspase-3-dependent apoptotic pathway.